It is important to tell your doctor or pharmacist what medicines you are
already taking, including those bought without a prescription and herbal
medicines, before you start treatment with this medicine. Similarly, check
with your doctor or pharmacist before taking any new medicines while taking
this one, to ensure that the combination is safe.

The amount of topiramate in the blood may be decreased by the following
medicines:

* carbamazepine

* phenobarbital

* phenytoin

* primidone.

Topiramate may increase the blood level of phenytoin, and people taking this
combination of antiepileptic medicines should have the amount of phenytoin
in their blood monitored.

It is recommended that people who are taking any antiepileptic medicines
should avoid taking the herbal remedy St John's wort (Hypericum perforatum).
This is because St John's wort may affect the level of antiepileptic
medicines in the blood and could increase the risk of seizures.

Topiramate may make combined oral contraceptive pills less effective by
reducing the blood level of oestrogen. For this reason, women using combined
oral contraceptives should be prescribed a pill(s) containing at least 50
micrograms of oestrogen. Alternatively, non-hormonal methods of
contraception such as condoms should be used to prevent pregnancy. If you
are taking an oral contraceptive with topiramate you should tell your doctor
if you experience any changes in your menstrual bleeding, because this may
mean that your pill is becoming less effective at preventing pregnancy.

There may be an increased risk of drowsiness and sedation if this medicine
is taken with any of the following (which can also cause drowsiness):